Methine dyes



United States Patent 3,243,298 METHINE DYES Marcel Jan Libeer, Henri Depoorter, and Gerrit Godfried van Mierlo, Mortsel-Antwerp, and Raymond Gerard Lemahieu, Wervik, West Flanders, Belgium, assignors to Gevaert Photo-Producten N.V., Mortsel, Belgium, :1 Belgian company No Drawing. Filed May 28, 1962, Ser. No. 197,925 Claims priority, application Great Britain, May 29, 1961, 19,269/ 61 8 Claims. (Cl. 96105) This invention relates to new methine dyes, to processes for making them and the photographic emulsions containing them.

According to one feature of the present invention'there are provided methine dyes containing at least one heterocyclic nucleus derived from 1,2 condensed benzimidazole compounds to one of the following general formulae )u1 Vz N/ \A l V3 (BM-1 and V1 (Ba-1 I (Bu-1 (s A L an, em N I N CH2 (I Wherein:

V V V and V each represent (the same or different) a hydrogen atom, an alkyl radical, an aryl radical, an aralkyl radical, a substituted alkyl radical e.g. a trifluoromethyl radical, a substituted aralkyl radical, a substituted aryl radical, a halogen atom, a hydroxyl group, an alkoxy group, an acyloxy group, a nitrile group, a carboxyl group, a carbalkoxy group, a carbamyl group, a substituted carbamyl group, a nitrogen containing group such as an amino group, an acylamino group, a sulphonylamino group, a 'hydrazino group, an alkyl sulphonyl group, a sulphonic acid group, a sulphonic acid ester group, a sulphonainide group, an acyl group, an arylazo group or the atoms necessary to complete an adjacent benzene nucleus,

(B) represents (in the case n 1) one or more equally or differently substituted and/or not substituted methylene groups,

(B) represents (in the case p 1) one or more equally or ditferently substituted and/or not substituted methylene groups,

pv and it each represents a positive integer of at least 1 and n+p 5, and

A represents a methylene group, a substituted methylene group, an hetero atom such as oxygen and sulfur, a group such as 3,243,298 Patented Mar. 29, 1966 "ice wherein Y represents an alkyl radical, an aralkyl radical, an aryl radical, a carbalkoxy radical, or a V1, V2, V V A, (B) (B) have the same values as in the general Formulae I and II described above,

spectively either or not the same value as V V V V A, (B) (B) in the same molecule.

R and R each represent respectively a substituent of the type contained in cyanine dyes on the cyanine nitrogen atom, e.g. an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a buty-l group, an isobutyl group, a substituted alkyl group such as an allyl group (vinyl methyl), a B-hydroxyethyl group, a fi-acetoxyethyl group, an alkylene sulphonic acid group as described in the French patent specification 1,223,289 and the German patent specification 929,080 such as a sulphoethyl group, a sulphopropyl group, -a sulphobutyl group, an alkylcne sulphate group as described in the French patent specification 1,149,769 such as a propylsulphate group or a butylsulphate group, a benzyl group (phenyl methyl), a carboxymethyl group, a caribox ymethyl group as described in the German patent specification 704,141, a carboxybenzyl group, a sulphobenzyl group, the group wherein A and B have the same significance as set forth in Belgian patent specification 568,759 such as a sulphocarbomethoxy methyl group, .an w-sulphocarbopropoxy methyl group, an w-sulphocarbobutoxy methyl group, a p (w sulphocarbobutoxy) benzyl group, the group AWNHVB wherein A, W, V and B have the same significance as set forth in Belgian patent specification No. 569,130 such as a N-(methylsulphonyl)- carbarnyl methyl group, -(acetyl-sulphonarnido)-propyl, a S-(acety-lsulphonamido) -butyl group, the group wherein A has the same significance as described in the Belgian patent specification No. 568,840, an aryl group such as a phenyl group, a carboxyphenyl group, or a cycloalkyl group such as a cyclohexyl group,

L L and L each represents a methine group (e.g. =CH, :C.CH3, =C.C H :C.C3H7,

(wherein R and R are -a hydrogen atom, an alkyl group or an aryl group), =C.(CH=),D (wherein D represents a heterocyclic radical, and r represents Zero or an integer from 1 to 6), or a methine group which forms part of a heterocyclic or isocyclic ring such as a cyclopentadiene ring,

d represents an integer from 1 to 3, and

X represents an anion such as a chloride ion, a bromide ion, an iodide ion, a perchlorate ion, a benzene sulphonate ion, a p-tolusulphonate ion, a methylsulphate ion, an ethylsulphate ion, and a propylsulphate ion.

V'I, VZ, 3a 4, L2: L3 A: )n1: )p'-1 R1 R and X have the same values as described in Formulae III, IV and V,

r represents an integer from 1 to 4,

m represents an integer from 1 to 2,

Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing 5 or 6 atoms in the heterocyclic ring e.g. a nucleus of the thiazole series (e.g. thiazole, 4-methylthiazole, 4-phenylthiazole, S-methylthiazole, S-phenylthiazole, 4,5-dimethylthiazole, 4,5-diphenylthiazole, 4-(2-thienyl-thiazole), those of the ben-zothiazole series (e.g. benzothiazole, 4 chlorobenzothiazole, S-chlorobenzothiazole, 6-chlorobenzothiazole, 7- chl orobenzothiazole, 4-rnethylbenzothiazole, 5-methylbenzothiazole, 6 methylbenzothiazole, 5 bromobenzothiazole, 6-bromobenzot-hiazole, 4-phenylbenzothiazo1e, S-phenylbenzothiazole, 4-methoxybenzothiazole, S-methoxybenzothiazole, 6-methoxybenzothiazole, S-iodobenzothiazole, 6-iodobenzothiazole, 4-ethoxybenzothiazole, '5- ethoxybenzothiazole, 4,5,6,7-tetrahydrobenzothiazole, 5,6- dimethoxybenzothiazole, 5,6 dioxymethylenebenzothiazole, S-hydroxybenzothiazole, 6-hydroxybenzoth iazole, 5,6-dimethylbenzothiazole), those of the naphthothiazole series (e.g. naphtho[2,1-d]thiazole, naphtho[1,2-d]thiazole, 5-methoxynaphtho[1,2-d]thiazo1e, S-ethoxynaphtho [1,2-d]thiazole, 8 methoxynaphtho[2,l-d]thiazole, 7- methoxynap'htho[2,1-d]thiazole), those of the thionaphtheno[7', 6'-d]thiazo1e series (e.g. 4-methoxythiona'phtheno[7,6'-d]thiazo1e), those of the oxazole series (eig, 4-methyloxazole, S-methyl-oxazole, 4-phenyloxazole, 4,5- diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole, 5- phenyloxazole), those of the benzoxazole series (e.g. benzoxazole, S-chlorobenzoxazole, S-methylbenzoxazole, S-phenylbenzoxazole, 6-methylbenzoxazole, 5,6-dimethylbenzoxazole, 4,6 dimethylbenzoxazole, 5 methoxybem zoxazole, 6-methoxybenz-oxazole, S-hydroxybenzoxazole, 6-hydroxybenzoxazole), those of the naphthoxazole series (e.g. naphtho[2,1 d] oxazole, naphtho[1,2 d]oxazole), those of the selenazole series (e.g. 4-methylselenazole, 4-phenylse1enazole), those of the benzoselenazole series (e.g. 'benzoselenazole, 5-chlorobenzoselenzazole, S-methoxybenzoselenazole, 5 hydroxybenzoselenazole, 4,5,6,7-= tetrahydrobenzoselenazole), those of the naphthoselena zole series (e.g. naph-tho[2,1-d] selenazole, naphtho[1,2-d] selenazole), those of the thiazoline series (e.g. thiazoline, 4-methylthiazoline, 4-hydroxymethyl-4-methylthiazoline, 4,4-bis-hydroxymethylthiazoline, 4-acetoxymethyl-4-methylthiiazoline, 4,4-bis-acetoxymethyl-thiazoline), those of the thiazolidine series (e.g. 2-benzothiazolylidene-4- thiazolidone), those of the oxazoline series (e.g. oxazoline, 4-hydroXymethy1-4-methyloxazoline, 4,4 1bis hydroxymethyloxazoline, 4-acetoxymethyl-4-methyloxazoline, 4,4- bis-acetoxyrhethyloxazoline), those of the oxazolidine series, those of the selenazoline series (e.g. selenazoline), those of the Z-quinoline series (e.g. the quinoline, 3- methylquinoline, S-methylquinoline, 7-methylquino-line, S-methylquinoline, 6-chloroquinoline, 8-chloroquinoline, 6-methoxyquino1ine, 6-ethoxyquinoline, 6-hydroxyquino-- line, 8-hydroxyquinoline etc), those of the 4-quino1ine; series (e.g. quinoline, 6-rnethoxyquin0line, 7-met-hylquinoline, S-methylquinoline), those of the, l -is oqpino;-

line series (e.g. isoquinoline, 3,4-dihydroisoquinoline), those of the 3-isoquinoline series (e.g. isoquinoline), those of the 3,3-dialkylindolenine series (e.g. 3,3-dimethyl indolenine, 3,3,S-trimethylindolenine, 3,3,7-trimethylindolenine), those of the pyridine series (e.g. pyridine, 5- met'hylpyridine), or those of the benzimidazole series (erg. l-ethylbenzimidazole, l-phenylbenzimidazole, 1- ethyl-S,6-dichlorobenzimidazole, 1 hydroxyethyl-5,6-dichlorobenzimidazole, 1-ethyl 5-chlorobenzimidazole, 1- ethyl 5,6 dibromobenzimidazole, l-ethyl-S-chloro-6- aminobenzimidazole, 1-ethyl-5-chloro-6-brornobenzimidazole, 1 ethyl 5 phenylbenzimidazole, 1-ethyl-5-fluorobenzimidazole, 1-ethyl-S-cyanobenzimidazole, l-(B-acetoxyethyl) 5 :cyanobenzimidazole, 1-ethyl-5-chloro-6- cyano benzimidazole, 1-ethyl-5-fluoro-6-cyano benzimidazole, 1-ethyl-5-aeetyl-benzimidazole, 1-ethy1-5-ch1oro-6- fluorobenzimidazole, 1-ethyl-5-carboxybenzimidazole, 1- ethyl-7-carboxybenzimidazole, 1-ethyl-5-carbethoxybenzimidazole, 1-ethyl-7-carbethoxybenzimidazole, 1-ethyl-5- sulphonamidobenzimidazole, 1 ethyl-S-N-ethylsulphonamidobenzi'midazole) More particularly We provide also new methine dye salts which difier from the methine dye salts according to the general Formulae III, IV, V, VI and VII, therein that the radical, which is bound to the quaternated nitrogen atom, carries a negative charge and that it forms a betaine-like structure With the quaternated nitrogen atom. The eventual obtaining of a 'betaine-like structure depends on the nature of the used quaternating agent. These methine dye salts according to this invention, having a betaine-like structure are represented by the following general formulae:

radical as described in the US. patent specification 2,238,231, an alkylene I OH radical as described in the Belgian patent specification 568,840, a --ACOO--BSO O- radical as described in the Belgian patent specification 568,759, wherein each of A and B represents an alkylene radical a radical wherein each of V and W represents a SO radical, a

Further we provide new merocyanine dyes represented by the following general formulae:

V V V V A, (B) (B) have the same value as in the general Formulae I and II,

R L L and L have the same value as in Formula III,

e represents an integer from 1 to 2, and

P and Q each represents an organic group, at least one of these groups being an electronegative group such as a cyano group or a COOR group, wherein R represents a hydrogen atom or an alkyl radical such as a methyl group or an ethyl group, e.g. an alkyl radical of the formula C H wherein w represents an integer from 1 to 4; the radical may also represent a nucleus with negative character such as those of the pyrazolone series (e.g. 3-methy1-1- phenyl-S-pyrazolone, l-phenyl-S-pyrazolone, I-(Z-be-nzothiazolyl) S-methyl-S-pyrazolone, etc.), those of the isoxazolone series (e.g. 3-phenyl-5(4H)-isoxazolone, 3-rnethyl-5(4H)-isoxazolone etc.), those of the oxindole series (e.g. l-alkyloxindoles etc.), those of the 2,4,6- trikethohexahydropyrimidine series (e.g. barbituric acid or Z-thiQbarbit-uric acid as well as their l-alkyl (e.g. 1- methyl, l-ethyl, l-n-propyl, l-n-heptyl, etc), or 1,3- dialkyl (e.g. 1,3-dimethy1, 1,3-diethyl, 1,3-di-n-propyl, 1,3-di-isopropyl, 1,3-dicyclohexyl, 1,3-di(B-methoxyethyl), or 1,3-diaryl (e.g. 1,3-dip'henyl, 1,3-di(p-chlorophenyl), 1,3-di(p-ethoxycarbonylphenyl), or l-aryl (e.g. l-phenyl, I-p-chlorophenyl, I-p-ethoxycarbony1phenyl), or 1-alky1-3-aryl (e.g. I-ethyl-3-phenyl, 1-n-hepty1-3- phenyl) derivatives), those of the 2-thio-2,4-thiazolidinedione (rhodanine) series (e.g. 3-ethyl-2-thio-2,4- thiazolidinedione, 3-ally1-2-thio-2,41:hiazolidinedione, 3- phenyl-Z-thio-Z,4-thiazolidine-dione), those of the 2-oxo- (3H)-irnidazo[1,2-a]pyridine series, those of the 5,7- dioXo-6,7-dihydro-5-thiazolo[3,2-a] pyrimidine series (e.g. 5,7-dioxo-3-phenyl-6,7-dihydro-5-thiazolo[3,2-a] pyrimidine), those of the 2-thio-2,4-oxazolidinedione series (e.g. 3ethyl-2-thio-2,4-oxazolidinedione), those of the thianaphthenone series (e.g. 3-(2H)-thianaphthenone) those of the 2-thio-2,5-thiazolidined ione series (e.g. 3-ethyl-2- thio-2,5-thiazolidinedione), those of the 2,4-thiazolidinedione series (e.g. 2,4-thiazolidinedione, 3-ethyl-2,4-thiazolidinedione, 3-phenyl-2,4-thiazolidinedione, 3-(l-naphthyl)-2,4-thjazolidinedione), those of the thiazolidinone series (e.g. 4-thiazolidinone, 3-ethyl-4-thiazolidinone, 3- phenyl-4-thiazolidinone. 3-alpha-naphthyl-4-thiazolidinone), those of the 4-thiazolinone series (e.g. Z-ethylmercapto-4-thiazolinone, 2-alkylphenylamino-4-thiazolinone, 2-diphenylamino-4-thiazolinone), those of the 2- imino-4-0Xaz0lidinone (p'seudohydantoin) series, those of the 2,4-imidazolinedione (hydantoin) series (e.g. 2,4- imidazolinedione, 3-ethyl-2,4-imid'azolinedione, 3-rpheny1- 2,4-imidazo1inedione, 3( I-naphthyl) -2,4-imidazolinedione, 1,3-diethyl-2,4-imidazolinedione, 1-ethyl-3-phenyl- 2,4-irnidazolinedion, l-ethyl-3-(l-naphthyl-2,4-imidazolinedione, 1,3-diphenyl-2,4-imidazolinedione, those of the 2-thio-2,4-imidazolinedione (Z-thiohydantoin) series (e.g. Z-thio-Z,4-imidazolinedione, 3-ethyl-2-thio-2,4-imidazolinedione, 3-phenyl-2-thio-2,4-imidazolinedione, 3-(l-naphthyl)-2-thio-2,4-imidazolinedione, 1,3-diethy1-2-thio-2,4- imidazolinedione, l-ethyl-3-phenyl-2-thio-2,4-imidazolinedione, 1-ethyl-3- l-naphthyl) -2-thio-2,4-imidazolinedione, 1,3-diphenyl-2-thio-2,4-imidazolinedione), or those of the S-imid azolinone series (e.g. 2-n-propylmercapto-5- imidazolinone), (especially a heterocyclic nucleus with negative character containing 5 to 6 atoms in the hetero cyclic ring, 3 to 4 of said atoms being carbon atoms, one of said atoms being a nitrogen atom, and one of said atoms being a nitrogen atom, an oxygen atom or a sulphur atom).

In the preparation of methine dye salts, merocyanine dyes, rhodacyanine dyes, polymerocyanine dyes and styryl dyes, according to this invention, 1,2 condensed benzirnidazolium quaternary salts are used represented by the general formulae:

and

wherein V1: V2 V3: V4, A: )n1 )p1: P R1 and X have the same significance as set forth above.

The 1,2-condensed benzimidazolium quaternary salts according to formulae X and XI can either directly be converted by one of the known methods into a methine dye, or a dye intermediate currently used in the chemistry of cyanine dyes can be formed in order to obtain therewith the methine dye.

Methine dye salts, merocyanine dyes, rhodacyanine dyes, polymerocyanine dyes and styryl dyes according to the present invention may be obtained by starting from these new 1,2-condensed benzimidazolium quaternary salts or dye intermediates by application of the usual condensation methods known to those skilled in the art.

The following description of some methods is not complete and therefore is not to be considered as limiting the scope of our invention but merely as a survey of the most usual condensation methods.

New asymmetrical methine dye salts according to the present invention-can be prepared by condensing 1,2- condensed benzimidazolium quaternary salts of the general Formulae X and XI with a cycloammonium quaternary salt represented by the following formula:

(XII) Wherein:

R X, Z and m have the same value as forth above in Formulae VI and VII, and

D represents a halogen atom, an alkylmercapto group, an aryl mercapto group, a lit-arylamino vinyl group, a S-arylamino-L3 -butadienyl group, a fialkylmercapto vinyl group, a ,B-arylmercapto vinyl group, a fi-acetanilido vinyl group or a 8-p-tolusulphanilido vinyl group, which vinyl groups may carry a substituent.

The condensations are advantageously carried out in the presence of a basic condensing agent, for example a trialkylamine such as triethylamine, a dialkylaniline, a heterocyclic tertiary amine such as pyridine or N-alkylpiperidine or the like. The condensation can also be carried out in the presence of an inert diluent such as methanol, ethanol, 1,4-dioxane, etc.

New asymmetrical methine dye, salts according to the present invention can also be prepared by condensing 1,2-condensed benzimidazolium quaternary salts of the general Formulae X and XI with a heterocyclic base known in cyanine dye chemistry, of the following formula:

Wherein:

L L R Z and, m have the same value as set forth above in Formulae VI and VII, and

Y represents a reactive functional group such as an oxygen atom, a sulphur atom, a selenium atom or an aryl-N=group.

The condensations of this type are advantageously carried out in acid medium or in the presence of a compound forming an acid medium, e.g. in the presence of an acid anhydride such as acetic anhydride.

New asymmetrical methine dye salts according to the present invention can also be prepared by condensing intermediates represented by the following formulae Wherein:

D represents an alkylmercapto group, an arylmercapto group, an arylamino group, an acetanilido group or ptolusulphanilido group,

R2: L1: L2: L3, l' V'2, V'Z! a y,( )n-1, )p'-1a d and X have the same significance as set forth above with cycloammonium quaternary salts containing a methyl group in ozor 'y-position such as those represented by the general Formula XII where D is a methyl group.

10 The condensations of this type are advantageously carried out in the presence of a basic condensing agent.

New asymmetrical methine dye salts according to the present invention can also be prepared by condensing intermediates represented by the following formulae Wherein:

Y: R2, L1! L2 L3: V"1, VZ, V'Q: V219 A: )n-1, (B') and d have the same significance as set forth above with cycloammonium quaternary salts containing a methyl group in OL- or 'y-position, such as those represented by the general Formula XII but wherein D repreents a methyl group.

The condensations of this type are advantageously carried out in the presence of an acid anhydride.

Other asymmetrical methine dye salts according to the present invention can be prepared by condensing respectively a compound of Formula X with a compound of Formula XIV, a compound of Formula XIII with a compound of Formula XI, a compound of Formula XIII with a compound of Formula X, and a compound of Formula XIV with a compound of Formula XI.

Some of the intermediates represented by the Formula XIII or XIV can be prepared by condensing a 1,2-condensed benzimidazolium quaternary salt represented by the Formulae X and XI with a compound represented by one of the formulae:

' 1,2-condensed benzimidazolium quaternary salt of the Formula X with a compound of the Formula XIII, or a 1,2-condensed benzimidazolium quaternary salt of the Formula XI with a compound of the Formula XIV, the radicals 1 'Z 's ii, )p la )n-17 2 ing the same significance as V V V V A, (B) (B) and R respectively.

The new symmetrical methine dye salts according to the present invention can also be prepared by condensing a 1,2-condensed benzimidazolium quaternary salt represented by the Formula X or XI with an ortho-carboxylic acid alkyl ester, such as ethyl ortho-formate, advantageously in a nitrobenzene solution, or in the presence of a carboxylic anhydride e.g. acetic anhydride.

The new betaine-like methine dye salts according to the present invention are, depending on the betaine-like radical, prepared analogously to the methods described in the French patent specification 1,149,769, the French patent specifications 1,223,289 and 2,238,231, the German patent specification 929,080 and the Belgian patent specifications 568,759, 568,840 and 569,130. The preparation of such dye salts is further illustrated in the examples of the present invention.

The new merocyanine dyes according to the present invention can be prepared by condensing a 1,2-condensed benzimidazolium quaternary salt represented by the Formula X or XI with heterocyclic compound represented by the formula:

(XVI) Wherein:

P, Q, L L L and e have the same significance as described in Formulae VIII and IX, and

E represents a reactive negative atom or grouping, eg a halogen atom, such as a chlorine atom, a bromide atom, or an iodine atom, a cyano group, an alkylor arylmercapto group, an alkoxy group, an arylamino group, an acetarylido group, a p-tolusulphanilido group etc.

The new diand tetramethine merocyaninc dyes according to the present invention can also be prepared by condensing an intermediate represented by the Formula XIII or XIV given above, with a compound represented by one of the following formulae:

/C=LaCH3 and CH2 Q Q (XVIIa) (XVIII?) Wherein:

P, Q and L have the same significance as set forth above.

The new styryl dyes according to the present invention can be prepared by condensing a 1,2-condensed benzimidazolium salt according to Formula X or XI with a p-dialkyl-aminobenzaldehyde advantageously in the presence of a carboxylic acid anhydride, for example acetic anhydride.

Hereinafter follows the description of some methods for the preparation of heterocyclic bases corresponding to Formulae I and II. These methods are illustrated by reaction schemes and detailed examples of preparation. These methods, however, are not limiting the scope of our invention. The preparations are divided in classes of analogous preparations and each class is illustrated by one or more detailed examples of preparations. The preparations of the bases are indicated by the letter A, which is preceded by a number indicating the class of the preparation and followed by a serial number.

This classification facilitates the survey of the several preparation methods and the reference thereto in the description of the preparations of the quaternary salts and the heterocyclic bases.

is prepared according to W. Reppe et al., Ann. 596, 209 (1955).

Preparation 0AO2.2,3 dihydro 1H-pyr'ro1o[1,2-a] naphtho[2,3-d]irnidazole:

CLASS 1A The heterocyclic bases of this class are prepared ac cording to the following reaction scheme, which was elaborated by K. H. Saunders, J. ChemfSoc. 3275 (1955):

First step:

Vi CII2)n-l I-IN A Vzx 2C-(C 2)n-i Va- N 0 2 -1 V2- N A V N02 H2C CH2)n-1 (III) Second step:

(III) V1 (CH2) p1 Va NH: HzC (CH2)n-1 Third step:

l (CH2)p-l Drazotize V N A Cyclize NnN3 i nitrobenzene Va Na zC-( 2)u1 l H2) p-l V2 N A.

G-. (CH2)u-i Wherein:

R representsa nitro group or a halogen atom, and A, V V V V n and p have the same significance as described above.

The first reaction step is carried out according to different methods which depend on the structure of the intermediates and the chosen reaction medium. The second reaction step is always carried out in nearly the same way. Just as the first reaction step, the third reaction step is carried out according to different methods. All these methods are illustrated by. detailed preparations. The intermediates and the heterocyclic bases which are prepared according to these detailed preparations are listed in Table 1A.

(1 Detailed preparations illustrating the first reaction step of Class 1A Preparation a: N-(2-nitro-4-chlorophenyl)-pyrrolidine is prepared as follows:

96 g. of 2,5-dichloronitrobenzene are added to 71 g. of pyrrolidine at a temperature of 50 C. This temperature is maintained for 15 min. on a water-bath. By adding the reaction product precipitates and is sucked 01f. Recrystallization from i-sopropanol yields 102 g. of N-(2- nitro-4-chlorophenyl)-pyrrolidine. Melting point: 73 C.

Preparation b: N-(2-nitro-4-fluorophenyl)-pyrrolidine is prepared as follows:

76.4 g. of 2,5-difiuoronitrobenzene prepared according to Weygand, Ber. 84 (1951), 107 is added dropwise with stirring to 89 cm. of pyrrolidine on a water bath at 50 C. Heating is continued for further 10 min. at 90 C. The reaction mixture is poured into water and the oily substance is extracted with benzene. After washing of the benzene-extract with water and drying with sodium sulphate, the benzene is distilled off under reduced pressure. The residue is recrystallized from isopropanol. Melting point: 48 C. Yield: 88 g.

Preparation c: N-(2-nitro-4-carbethoxyphenyl)-pyrrolidine is prepared as follows:

15.6 g. of pyrrolidine are added dropwise to a hot solution boiling temperature) of 23 g. of 3-nitro-4- chl-oroethylbenzoate (prepared according to Hiibner, Ann. 222, 183) in 60 cm. of anhydrous ethanol. After adding pyrrolidine the reaction mixture is refluxed for 1 h. by heating on a water-bath. The reaction mixture is poured into water and the formed precipitate is sucked off. Melting point: 78 C. Yield: 26 g.

Preparation d: N-(2-nitro-4-carbethoxy-5-chlorophenyl) -pyrrolidine is prepared as follows:

A solution of 55 g. of 2-chloro-4,5-dinitro-ethylbenzo ate in 250 cm. of methanol is added dropwise with stirring at 50 C. to 28.4 g. of pyrrolidine. After heating for min. on a water-bath followed by cooling the precipitate is sucked off, washed with a mixture of alcohol and water and recrystallized from methanol. Melting point: 105 C. Yield: 45 g.

The starting product 2-chloro-4,S-dinitroethylbenzoate is prepared as follows:

143 g. of 2-chloro-4,5-dinitrobenzoic acid prepared according to Goldstein and Studer, Helv. 20 (1937) 1409 and 140 cm. of thionyl chloride are heated on a water bath for 3 h. After evaporating the excess of thionyl chloride, 220 cm. of ethanol are slowly added. The obtained mixture is poured into 2 l. of water. The precipitated ester is sucked off and washed with water. After recrystallizing twice from ethanol the ester obtained melts at 78 C. Yield: 157.5 g.

Preparation e: 2 -(pyrrolidino) 5 (pyrrolidino sulphonyl)-nitrobenzene is prepared as follows:

102.4 g. of 3 nitro 4 chlorobenzene sulphochloride (preparation described in Ber. 24 (1891) 3.190) are added portion-wise to 148 cm. of pyrrolidine at 50 C. Heating is continued for min. on a boiling water-bath. The reaction mixture is poured into water and the pre- (2) Detailed preparation illustrating the second reaction step of Class 1A Preparation g: N-(2-amino-4 chlorophenyl)-pyrrolidine is obtained by catalytic reduction in ethanol of N-(2- nitro-4-chlorophenyl) pyrrolidine. After evaporation of the solvent a brown oily residue is obtained, which is used as such in the next reaction step.

(3) Detailed preparations illustrating the third reaction step of Class 1A Preparation h: 7 chloro 1,2,3,4-tetrahydropyridino [1,2-a1benzimidazole:

H: o N CIHz CH ell L is prepared according to K. H. Saunders J. Chem. Soc. 3275 (1955).

Preparation i: 6 chloro 2,3 dihydro-lH-pyrrolo [1,2-a] benzimidazole:

is prepared as follows:

82.4 g. of N-(2-amino-4-chlorophenyl)-pyrrolidine are dissolved in 625 cm. of 2N hydrochloric acid and diazotized with a solution of 29.4 g. of sodium nitrite in 70 cm. of water.

g. of sodium acetate in 650 cm. of water. The formed azide is sucked off and dissolved in 500 cm. of nitro benzene. This solution is added. dropwise to 500, cm. of nitrobenzene, heated at 170 C. When the reaction is over, the nitrobenzene is distilled off under reduced pressure until a residual volume of about cm. After cooling, the formed benzimidazole compound crystallizes out and is sucked off. The 6 chloro-2,3-dihydro-1H- pyrrolo[1,2-a]benzimidazole base is purified by recrystallization from a mixture benzene/hexane. Yield: 37.2 g. Melting point: 137 C.

Preparation j: 8 chloro-3,4-dihydro-1H-1,4 oxazino [4,3-a1benzimidazole is prepared according to K. H. Saunders, 1. Chem. Soc. 3275 (1955).

The obtained-solution is then poured into. an aqueous solution of 35.3 g. of sodium azide and 168 A, V V V n and p have the same significance as above, and

V represents the radicals which can be introduced by the Sandmeyer or Schiemann reaction.

The first and second reaction step are always carried out in the same way and are resp. illustrated by the detailed preparations k and l.

The third reaction step is carried out according to three diiferent methods which are illustrated by the detailed preparations m, n and o.

The heterocyclic bases which are prepared analogously to these detailed preparations are listed in Table 2A.

(1 Detailed preparation illustrating the first reaction step of Class 2A Preparation k: 6-brorno-7-nitro-2,3-dihydro-lH-pyrrolo [1,2-a]benzimidazole is prepared as follows:

19.1 g. of 6 bromo 2,3-dihydro-1H-pyrrolo[1,2-a] benzimidazole prepared according to preparation 1A06 are dissolved in 60 'crn. of concentrated sulphuric acid, and nitrated at -5 C. with a mixture of 7.7 cm. of nitric acid (d:1.42) and 25 cm. of concentrated sulphuric acid. The reaction mixture is poured into water, neutralized with ammonium hydroxide and after sucking 01f the precipitate is recrystallized from ethanol. Melting point: 201 C. Yield: 17 g.

(2) Detailed preparation illustrating the second reaction step of class 2A.

Preparation l: 6-brorno-7-amino-2,3-dihydro-lH-pyrrolo[1,2-a]-benzimidazole is prepared as follows:

15.2 g. of 6-bromo-7-nitro-2,3-dihydro-lH-pyrrolo- [1,2-a] benzimidazole are reduced in methyl glycol in the presence of Raney nickel. After reduction, the solvent is evaporated and the amine is recrystallized from ethanol. Melting point: 264 C. Yield: 10.2 g.

(3) Detailed preparations illustrating the third reaction step of class 2A Preparation m: 6-bromo-7-cyano-2,3-dihydro-lH-pyrrolo[ 1,2-a]-benzirnid azole:

is prepared as follows:

' with water and suspended in water.

18 9.2 g. of 6 bnomo 7 amino-2,3-di-hydro-lH-pyrrolo- [1,2-a]benzimidazole are dissolved in a mixture of 30 cm. of water and 9 cm? of hydrochloric acid. Diazotation is carried out with a solution of 2.5 g. of sodium nitrite in 15 cm? of water. The diazonium salt is neutralized with sodium carbonate and while stirring poured into a solution of 6.89 g. of cuprous cyanide and 12.3 g. of potassium cyanide in cm. of water. Stirring is continued for 30 min. at room temperature and a further 15 min. on a water-bath at 50 to 60 C. After cooling, the precipitate is sucked off. The base is purified by sublimation (200 C./2 mm. Hg.) and recrystallized from a mixture of benzene and n-hexane. Melting point: 224 C. Yield: 4.7 g.

Preparation n: 7-chloro-2,3-dihydro-1H-pyrrolo[l,2-a]- benzimidazole of the formula:

H2 C Cl III ([3112 C C H:

is prepared as follows:

A suspension of 17.3 g. of 7-amino-2,3-dihydro-1H- pyrrolo[1,2-a]benzimidazole prepared according to W. Reppe, Ann. 596, 209 (1955) in 200 cm. of 5 N hydrochloric acid is diazotized with a solution of 7.2 g. of sodium nitrite in 30 cm. of water. The Obtained solution is added to a solution of 8 g. of cuprous chloride in 35 orn. of concentrated hydrochloric acid at 50-6() C. After cooling the precipitate is sucked off, washed By adding to this suspension a 25% aqueous solution of ammonia the heterocyclic base is set free and sucked off. After drying, recrystallization from benzene yields 4.1 g. of 7- chloro 2,3-dihydro 1H pyrrolo[1,2-a1benzimidazole. Melting point: 136 C.

Preparation 0: 7-fiuoro-2,3-dihydro-1H-pyrrolo[1,2-a]- benzimidazole of the formula:

is :prepared as follows:

43.6 g. of 7-amino-2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole according to W. Reppe, Ann. 596 (1955 209, are dissolved in a 31% aqueous solution of fluoboric acid and diazotized with a solution of 18.5 g. of sodium nitrite in 50 cm. of water. After neutralization with sodium carbonate under cooling the diazonium fluoborate obtained is sucked off and washed with methanol and ether. Yield: 58 g. Melting point: l80 C. (with decomposition).

This diazonium fl-uoborate is added portionwise to 250 cm. of boiling tetra'line in order to decompose the diazonium fluoborate in the corresponding fiuorocornpound. The supernatant tetraline is decanted and the residue is extracted with a warm 2 N hydrochloric acid solution. To liberate the base sodium carbonate is added. The base is extracted with chloroform and after evaporating the solvent, the residue is distilled under reduced pressure. Yield: 7 g. Boiling point: 166 C./3 Melting point: 124 C.

TABLE 2A First Reaction Step Second Re- Third Reaction Step action Step Starting produotI o' H; a? 6 .Q a? k 5 .5, "6 ots 4 H gone n 0 T3053 4.5%

g; g 2 g? g a? 2, a: g Chemical name of the heterooyclic 2:; w o Significance ofcu Q a, n.9,; g a. base (IV) Q8 m 2 g .211;! en 3311 elfa 2'1: egg on: gaze 5g: age: a5: 55 5am: a gs p .H .2 4 v1 V3 V4 2,25 we? See-E 5mg Ea; gas- 13:56 :18

m 2 m 2 'm m E Z (1) In the ease A=CH and p+n=4 H H H 7-amino-2,3-dihydro-1H-pyrrolo[1,2- 2A00 a1benzimidazole. -H Br H k 201 l 264 ON in 6-brom0-7-cyano-2,3-dihydro-1H- 224 2A01 pyrrololl,2-a1benzimidazole. H 01 H k 203 l 264 CN 111 fi-ehlor0-7-cyano-2,3-dihydro-1H- 215 2A02 pyrrol0[1,2-a]benzimidazole. H F H k 236 1 230 CN m 6-fiuoro-7-cyan0-2,3-dihydr0-1H- 210 2A03 pyrrol0[1,2-a]benzimidazole. H H H CN 111 7-cyano-2,3-dihydro-1H-pyrrolo 155 2A04 [1,2-a1benzirnidazole. H H H Cl 11 7-chloro-2,3-dihydr0-1H-pyrrolo 136 2A05 [1,2-a1benzimidazole. H H H .s F o 7-fiuoro-2,3-dihydro-1H-pyrr0lo 124 2A06 [1,2-a1benzimidazole.

(2) In the ease A=CH3 and p+n=5 H Br H k 184 l 217 ON 111 7-bromo8-cyano-1,2,3,4-tetrahydro- 210 2A07 pyridino[1,2-a]benzim1dazo1e. H 01 H 194 l 210 ON in 7-chloro-8-cyan0-1,2,3,4-tetrahydro- 212 2AO8 pyridino[1,2-a1benzimidazole. H F H k 264 1 199 ON in 7-fiuoro-8-cyan0-1,2,3,4-tetrahydro- 253 2A09 pyridin0[1,2-a]benzimidazole. H H H CN 111 S-cyano-l,2,3,4-tetrahydropyridino 194 2.410

[1,2-a1benzimidaz0le.

(3) In the case A=oxygenatom and p+n=5 H C1 H k 220 1 264 ON m 7-eyano-8-chl0r0-3,4-dihydr0-1H- 300 2A11 1,4-oxaz1no[4,3-a]benz1m1dazo1e.

1 W. Reppe Ann. 596 (1955) 209. 2 K. H. Saunders, J. Chem. Soc. (1955) 3277.

CLASS 3A Preparation 3A03.6 carboxy 7 chloro 2,3 di- HOOC is prepared as follows:

A solution of 5 g. of 6-carbethoxy-2,3-dihydro-1H- pyrrolo[1,2-a]'benzirnidazole (1AO6) in 15 cm. of ethanol and cm. of 2,5 N sodium hydroxide are refluxed for 5 min. After cooling the reaction mixture is slightly acidified with diluted acetic acid and the precipitate formed is sucked off and Washed with water and ethanol.

Yield: 4 g. Melting point: 300 C.

Preparation 3A02.-8 car-boxy- 2,3 dihydro 1H- pyrrolo[1,2-a]benzirnidazole:

is prepared analogously to preparation 3A01 starting from 8 carbethoxy 2,3 dihydro 1H pyrro-l0[1,2-a]- benzimidazole (1A07). Melting point: 310312 C.

hydro-1H-pyrro1o-[1,2-a]benzimidazole:

is prepared as follows:

C-OH HOOO- \Ny is prepared analogously to preparation 3AO1 starting from 6 carbethoxy 7 chloro 2,3 dihydro 1H- pyrrolo[1,2-a1-benzi-midazole (1A08). Melting point:

CLASS 4A This class concerns the preparation of acylamino substituted heterocyclic bases.

The following detailed preparation is given as an illustration:

Preparation 4A01.7-acetylamino 2,3 dihydro 1H- pyrr0lo[1,2-a]benzimidazole:

1-12 0 N on 8.65 g. of 7-arnino-2,3-dihydro-1Hpyrrolo[1,2-a]benzimidazole (2A00) prepared according to W. Reppe Ann. 596 (1955) p. 209 are suspended in 50 cm. of benzene. To this suspension is added dropwise 6.2 g. of acetic anhydride. The mixture is boiled for 15 min. and after 21 cooling the precipitated acetyl compound is sucked 01f. Recrystallization from ethanol yields 7.3 g. of 7-acetylamino 2,3 dihydro 1H pyrrolo[1,2-a]benzimidazole. Melting point: 250255 C. Two further recrystallizations from ethanol raise the melting point to 260262 C.

CLASS A This class concerns the preparation of 6-cyano-2,3- dihydro-lH-pyrrolo[1,2-a]benzimidazole.

Preparation 5A01.6-cyano 2,3 dihydro-1H-pyrrolo- [1,2-a]benzimidazole is prepared as follows:

18.3 g. of cuprous cyanide are added at reflux temperature to a solution of 40.3 g. of 6-bromo-2,3-dihydro-1H- pyrrolo[1,2-a]benzimidazole (1A05) in 200 cm. of nitrobenzene. The reaction mixture is refluxed for 90 min. and then cooled till 100 C. A solution of 34 g. of sodium cyanide in 100 cm. of water is added whereupon the mixture is shaken for 5 min. Then 40 cm. of chloroform and 40 cm. of water are added. The organic layer is separated, washed with a solution of sodium cyanide and twice with water. Finally the solution is boiled with decolourizing carbon, evaporated and recrystallized from ethanol. Melting point: 190 C.

CLASS 6A This class concerns the preparation of 6,11-dihydrobenzimidazolo[1,2-b1isochinoline.

Preparation 6A0] .6,ll-dihydro-benzimidazolo[1,2-b]

isoquinoline ICE m \N o Hz is prepared as follows:

24.8 g. of 3,6-dihydro-4,5-benzo-2-pyrone (prepared according to F. G. Mann and F. H. C. Stewart: J. Chem. Soc., 1954, 2819) and 18.1 g. of o-phenylene diamine are heated for h. at 250 in a sealed tube. The reaction mixture is distilled under reduced pressure, and the distillation product recrystallized from ethylacetate.

Yield: 16.7 g. Melting point: 202 C.

CLASS 7A This class concerns the preparation of 1,2,3,4,8,9,10,11- octahydrodipyridino[1,2-a: l,2'-a'] benzo[1,2-d:5,4-d]- diimidazole.

Preparation 7A01.1,2,3,4,8,9,10,11 octahydrodipyridino[1,2-a:1',2-a]-benzo[1,2-d:5,4-d']-diimidazole is prepared according to K. H. Saunders, J. Chem. Soc.

The heterocyclic bases corresponding to the general Formulae I and II are usually converted into quaternary salts for being used in the preparation of the methine dyes according to this invention. According to the used quaternating agent, a quaternary salt with a free anion or a quaternary salt with a betaine-like structure is obtained. Quaternating agents which are used in order to obtain a quaternary salt with a free anion are e.g. methyl iodide, ethyl iodide, ,B-carboxyethyl bromide, fi-hydroxy- 22 ethyl bromide, or the quaternating agents which are described in the British patent specifications 886,270 and 886,271 or the quaternating agents described in the French patent specification 1,223,289.

Quaternating agents which are used in order to obtain directly a quaternary salt with a betaine-like structure are e.g. compounds of the following formula:

(ems-( wherein m represents an integer from 1 to 5, such as propylene sulfate or butylene sulfate, which are more particularly described in the French patent specification 1,149,769 and the saltone-compounds described in the British patent specification 742,112.

In order to obtain either type of quaternary salts, a free heterocyclic nitrogen base as described above is reacted with one of the above quaternating agents usu ally in an excess of 15 to 20% and at a temperature comprised between 50 and C., either in the presence of a neutral diluting agent such as acetone or in a sealed tube.

The quaternary salts, which are used in the preparation of the methine dyes according to this invention, are mostly prepared according to the classical scheme by the reaction of the corresponding base with a quaternating agent.

The quaternary salts with the following structural formula:

Wherein:

V V V V R and X have the same significance as set forth above, can also be prepared according to the following reaction scheme:

Some detailed preparations are given as an example for the method of preparing the quaternary salts used in this invention. Quaternary salts used in this invention are classified in table Q. In this table are given: the reference number, the name of the quaternary salt, the reaction time, the reaction temperature and an indication whether a diluent or a sealed tube is used. The reference numbers of the quaternary salts are composed of the reference numbers of the corresponding bases followed by the letter Q and a number referring to the used quaternating agent.

The reference numbers for the used quaternating agents are the following:

Methyl iodide 1 Ethyl iodide 2 S-hydroxyethyl bromide 3 fi-carboxyethyl bromide 4 w-acetyl sulfonamidopropyl bromide 5 23 24 w-acetyl sulfonamidobutyl bromide 6 (b) 8-chloropyridino[1 2-a]benzimidazole: 8.8 g. of 8- Methyl sulphonyl carbamyl methyl bromide 7 aminopyrid1no[1,2-a]benz1m1dazole are dissolved 1n 80 (CH2)3 Q cm. of 5 N hydrochloric acid and diazotlzed wlth a solution of 3.7 g. of sodium nitrite in cm? of water. The O-SO2- 3 I 5 solution of the diazonium salt is poured into a solution of fl; a is a a iz y ammonlum y IOXl e an e preclpi a e igz jigg z 32? gggg g gfig gz l sucked off. Recrystallization from benzene-hexane ylelds rolo[1 2-a]benzimidazoli1i iodide is re ared as follows" of the benzimldazole base m P P Melting point: 207 0. of Y 9' H' yrroloilz'awelz lmldazole 10 (c) S-ethyl 8 chloropyridino[1,2-a]benzimidazolium z ig ig gi g% i if gi i iizgjigi 5532:23 3; iodide: 2 g. of 8-chloropyridino[1,2-a]benzirnidazole and 1.7 g. of ethyl iodide are heated for h. at 110 C. in a o 15 wit acetone an et er. 1e g. e ting porn a ove pomt: 220 C. 0

Preparation Full/1'23'dihy'dm'1H pyr' 2d) 5-ethyl 8 chloro 1,2,3,4 tetrahydropyridinofg g g glg a ag sfi g i gg iifpgsgi [1,2-a]benzirnidazolium iodide: 3 g. of the preceding and o f i y j i d 2 1 h at C quaternary salt are dissolved in ethylene glycol monoin a sealid tu he fift er cogliri the uaternar salt is methyl ethe-r and hydrogenated 80 m the presence h d h 27 3 g M 9 U FY1980 c of Raney nickel. After evaporation of the solvent 1.1 g. g et 09 1c 1 n .a. of 5-ethyl-8-chloro 1,2,3,4 tetrahydropyridino[1,2-a] h I 2 dih i benzirnidazolium iodide is obtained. Melting point:

2.-..;.;...;.:a.;a" r1 e P r 2A00-01.4 th 1- 'n -2,3-dih dro- 3.4 g. of 6-(Pyrrolidinosu1phonyl)-2,3-d1hydro-1H-pyr- ;i, g 'g gfi z g x 0 y rolo[1,2-a]benzin1idazole and 1.2 cm? of methyl iodide t are heated at 95 C. for 6 h. in a sealed tube. The quaterg nary salt formed is washed with acetone and ether. Melting point: above 270 C. Yield: 4.9 g. Hm OH Preparation 1A12Q2.5-ethy1-7-chloro-1,2,3,4-tetra- C CH2 1- hydropyridino[1,2-a]benzimidazolium iodide is prepared as follows:

6.2 g. of 7 chloro-1,2,3,4-tetrahydropyridino[1,2-a] CH3 benzirnidazole and 6.2 g. of ethyl iodide are heated for 1S P p as fOHPWSi 15 h. at 110 C. in a sealed tube. After cooling the formed 1% 0f Y 'PY l quaternary salt is washed with acetone and ether. Yield: lmldaZOle, P p? accofdlng PP 9 3 Making point above 250 (1955) 209, are drssolvedbyheating 111 cm. of meth- Preparation 1A20Q2.--8-chloro-l0-ethyl-3,4-dihydroanol- CHI-3 9 methyl loqlde 3Y6 addef1 dF0PW1$e 311d 1H [1,4]oXaZin0[4,3-a]benzimidazolium i i is 40 the mixture boiled for 15 min. The precipitated quarterpared as f ll nary salt 1s sucked off and washed with acetone and ether.

10.4 g. of 8-chlor o-3,4-dihyd=ro-1H[1,4]oxazino[4,'3-a] Meltlng p benzimidazole and 10 g. of ethyl iodide are heated for Acetylatlon the q f y Sal! Q '(B- 16 h. at 110 C. in a sealed tube. After cooling, the ref lf l- -gfiy 1H Py sulting quaternary salt is washed with acetone and ether. benzlmldalollum bromlde Yield: 17.9 g. Melting point: 186 C. 0 H

Preparation 1A 19-Q2.-5-ethyl-8-chloro-1,2,3 ,4-tetra- C hydropyridino[1,2-a1benzimidazolium iodide E2 2 Br- *CH: 01- N \CH2 NC NZ I- OHrCHrO-OO-Cfl Z is prepared as follows: (32m 3 4 g. of 5A01-Q3 are dissolved in 40 cm. of acetic anis prepared as follows: hydride and refluxed for 10 min. After cooling the mix- (a) 8-a -P$ [lll f q The P P- ture is precipitated with ether and the obtained product aration of 8-am1nopyr1d1no[1,2-a]benz1m1dazole is deis washed with water-free acetone and then with Waterscribed by Morgan & Stewart, J. Chem. Soc. 1292 (1938). free ether. Melting point: 208 C.

TABLE Q g? R v Reaction Used Melting the Chemical name of the quaternary salt Formula of the quaternizing agent iz i i ile tifr a sg l fil tul i t l ie of quaigrl'tnary quaiterngrv (1) In the case A=CH2 and p+n=4 A- h-,-'h -H- H I 2.2: 1 a 1 is. r

Q 1 ,2-fibniiniia zglniin iodideP 0' 2 5 15h 198 OAOl-Q3 4-(fi-hydroxyethyl 2,3dihydr0-1H- O 2 4-Br 6h pyrrolo[1,2-a1benzrm1dazohum brom1 e. A02-2 -4- h1-,-dhd--1H- 1- CH 0 Q [1 ,:i;i-g nap h tho[igdli uidazolilf 0 2 I 24 h no 250 See footnotes at end of table.

3,243,298 29 30 The following detailed examples illustrate the way of Example 4 obtaining the me-thine dyes according to this invention, The methine dye of the formula: without however, limiting the scope thereof.

Methine dyes which are prepared analogously to the &

detailed examples are given in table M. The dyes have 5 a reference number which is composed of the number of s H2O ON the example followed by their serial number. H=CH In the table are given: the reference number of the dye, Br its structural formula, the reference number of the start- HZON ing quaternary salt, the melting point of the obtained 0 m C211 dye, the absorption maximum and the value of log 6 of is prepared as follows: the dye. 2.1 g. of 4-ethyl-6-b-romo-7-cyano-2,3-dihydro-lH-pyr- Example 1 ro1o[1,2-a]benzimidazolium iodide (2A0l-Q2), 1.6 g. of 2-(fi-anilinovinyl)-3-ethylthiazolinium bromide dis- The methme dse 01 00 of the formula' solved in 25 cm. of acetic anhydride and 1.4 cm. of 5 E triethylamine are refluxed for 2 h. After cooling, the dye is sucked 01f and recrystallized twice from methanol. T mo 1 I Melting point: 260 C. Absorption maximum: 480

C =CH CH=CH=C=C III/1.. L02. 6: 5.135. Example 5 Car-It 32135 The methine dye (05-00) of the formula: is prepared as follows: &

6.3 g. of 4-ethyl-2,3-dihydro-lH-pyrrolo[1,2-a]benzimidazolium iodide (0A01Q2), 7 cm. of 1,3,3-triethoxy- Se H2O l-propene and 20 cm. of nitrobenzene are refluxed for I 5 min. After cooling, the dye is precipitated with ether. (|3=OHCH=O The precipitate is sucked off and recrystallized four times H2O N from ethanol. Melting point: 197 C. Absorption C2115 C2135 maxlmum: 596 is prepared as follows:

Example 2 A solution of 4.35 g. of 4-ethyl-8-chloro-2,3-dihydro- The methine dye (02-00) of the formula 1H-pyrrolo[1,2-a1benzimidazolium iodide (1A02-Q2) '0 H2 H2 N/ \CH2 1120 \N I12 Hz C C\ 3( 3=CH( 3= C /NO2S- N SO2N I o-o N o-o H2 In on; I 112 In is prepared as follows: and 5.6 0 g. of Z-acetanilidovinyl-B-ethyl selenazolinium To a solution of 4.9 g. of 4-methyl-6-pyrrolidinosuliodide in 30 cm. of acetic anhydride is refluxed for 5 fonyl 2,3 dihydro 1H-pyrrolo[.1,2-a]benzimidazolium min. with 3.2 cm. of triethylamine. The dyestulf crystaliodide (1A09Q1) in 25 cm. of nitrobenzene 3.5 cm. lizes on cooling and is purified by recrystallization from of ethylorthoformate are added. The mixture is boiled ethanol. Melting point: 285 C. Absorption maximum: for 2 h. The dye, which crystallizes on cooling, is puri- 462 m Log. 62 5.13. fied by recrystallization from dimethylformamide. Melting point: 320 C. Absorption maximum: 530 mp. Example 6 Log. s; 5.32. The methine dye (06-00) of the formula:

Example 3 The methine dye (03-00) of the formula: g:

H 02 1120 \N O I /S\ H2? I|\I- CN I 0 C CH=CH C 0104" H20 o=orroI-I=o-o c104 H C H \N/ I 3 M (IJH CH HzC N N+ 3 I C2H5 cm, om-Crn-o-Co-cm is prepared as follows: 65 is prepared as follows:

To 3.1 g. of 2-(fi-anilinovinyl)-3-ethyl-thiazolinium To 2.8 g. of 2-(B-phenyliminoethylidene)-3-ethyl-5- bromide and 3.1 g. of 4-(,B-hydroxyethyl)-7-cyano-2,3- methyl-2,3-dihydrobenzoxazole and 3.15 g. of 4-ethyldihydro 1H pyrrolo[1,2-a]benzimidazolium bromide 2,3-dihydro 1H pyrro1o[1,2-a1benzimidazolium iodide (2A04-Q3) in 20 cm. of acetic anhydride 2.8 cm. of (OAOl-QZ) in 30 cm. of acetic anhydride, 2.8 cm. of triethylamine are added and the reaction mixture retriethylamine are added. The reaction mixture is refluxed for 15 min. After cooling the dye is precipitated fluxed for 45 min. After cooling, the dye is precipitated with ether and converted into the perchlorate with sodium with ether and converted into the iodide which is puriperchlorate. The dye is recrystallized twice from ethfied by recrystallizing twice from ethanol. Melting anol. Melting point: 174 C. Absorption maximum: point: above 250 C. Absorption maximum: 470 m 476 m... Log. 62 5.12. Log. e! 4.99.

31 Example 7 The methine dye (07-00) of the formula:

H2 /O\ mo N OOII=CHC=C 11.0

CHrCHrOCO-CIT 02115 is prepared as follows:

To 5.6 g. of 2-(fi-phenyliminoethylidene)-3-ethyl-5- methyl-2,3-dil1ydrobenzoxazole and 5.6 g. of 4-(fl-hydroxyethyl -2,3-dihydro lH-pyrro1o[1,2-a]benzimidazolium bromide (0A01-Q3) in 50 cm. of acetic anhydride, 7

5.6 cm. of triethylamine are added with stirring. Stirring is continued for 2 h. at room temperature and for 15 min. at reflux. After cooling, the dye is precipitated with ether and converted into the perchlorate. The dye is recrystallized three times from ethanol. Melting point above 250 C. Absorption maximum: 474 mp. Log. 62 5.07.

Example 8 The methine dye (08-00) of the formula:

H: 0 H2O N T-I3G OCH=OH-O=C N H3C N+ is prepared as follows:

To 2.9 g. of 2-(,B-phenyliminoethylidene)-3-ethyl-5,6- dimethyl-2,3-dihydrobenzoxazole and 3.15 g. of 4-ethyl- 2,3-dihydro 1H pyrrolo[1,2-a]benzimidazoliun1 iodide (0A01-Q2) in 30 cm. of acetic anhydride are added 2.8

:cm. of triethylamine with stirring. Stirring is continued for 1 h. at room temperature and for 15 min. at reflux is prepared as follows:

6.8g. of l-ethyl-2-(N-p-tolusulphonyl-p-anilinovinyl)- 3-ethyl-5,6-dichlorobenzimidazolium chloride, 3.9 g. of 4- ethyl 2,3 dihydro-1H-pyrrolo[1,2-a1benzimidazolium iodide (0A0l- Q2 30 em. or pyridine and 3.5 Cm. of triethylamine are refluxed for 2 h. 7 The dye is precipitated W lth ether and purified byrecrystallization from a mixture of ethylene glycol monomethyl ether and water. ing pointabove250 C, A so p on maximum: 504 mp. v

Melt- Log. e; 5.20,

32 Example 10 The methine dye (10-00) of the formula:

is prepared as follows:

2.5 g. of l-ethyl-2-*(N-p-tolusulfonyl-B-anilinovinyl)-3- ethyl-5,6-dichlorobenzimidazolium chloride, 1.5 g. of 4- ethyl 7-chloro-2,3-dihydro-1H-pyrrolo[1,2-a]benzimidaz olium iodide (2A05-Q2), 10 cm. of nitrobenzene and 1.2 cm. of triethylamine are refluxed for 15 min. After cooling, the dye is precipitated with ether and recrystallized twice from ethanol. Melting point: above 250 C. Absorption maximum: 506mp. Log. at 5.24.

Example 11 The methine dye (11-00) of the formula:

is prepared as follows:

A mixture of 3.8 g. of 5-methyl-7-trifluoromethyl- 1,2,3,4-tetrahydropyridino[ 1,2-a]-benzimidazolium iodide (1A18-Q1), 3.3 g. of 2-(fl-phenylimino-ethylidene)-3- ethyl-2,3-dihydrobenzoselenazole, 25 cm. of acetic anhydride and 1.4 cm. of triethylamine is heated for 5 min. on a water-bath at 60 C. After cooling, the formed dyestuff is sucked off and three times recrystallized from ethylene glycol monomethyl ether. Melting point: 268 C. Absorption maximum: 512 m Log. e=5.024.

Example 12 The methine dye (12-00) of the formula:

is prepared as follows: 1

To a solution of 4.06 g. of 4-methyl-6-carbethoxy-7- chloro 2,3 dihydro-1H-pyrrolo[1,2-a]benzimidazoliuin iodide (1A08-Q1) and 3.55 g. of Z-(B-acetanilidovinyU- .3-ethylthiazolinium bromide in 60 cm. of absolute point: '75

ethanol, 1.4 cm. of triethylamine are dropwise added 'at the reflux temperature. The reaction mixture is refluxed for 20 min. After cooling the formed dyestuff is sucked off and washed with water, ethanol and ether. Thereupon the dyestuff is recrystallized from methanol. Melting 270 C. Absorption maximum: 470 mp. Log. e: 5.145.

33 Example 13 The methine dye (13-00) of the formula:

is prepared as follows:

A mixture of 3.62 g. of -methyl-6,l1-dihydrobenzim idazolo [l,2-b]isoquinolinium iodide (6A0l-Ql), 3.55 g. of 2-(5-acetanilidovinyl)-3-ethylthiazolinium bromide, 25 cm. of dimethyl formamide and 1.4 cm. of triethylamine is refluxed for '5 minutes. After cooling the reaction mixture is filtered and the filtrate is diluted with ether whereby the dyestufl precipitates. The dyestuff is sucked off and washed with water and ethanol whereupon it is recrystallized four times from ethanol. Melting point: 257 C. Absorption maximum: 456 m Log. 62 4.796.

Example 14 The methine dye (14-00) of the formula:

is prepared as follows:

A solution of 5.25 g. of 4-ethyl-8-ch1oro-2,3-dihyro- 1H pyrrolo[1,2 a]benzimidazolium iodide (1A02Q2) and 4.9 g. of 2-(,B-phenylimino-ethyl'idene)-3-ethyl-2,3- dihydro-benzoselenazole in 30 cm. of acetic ,anhydride is refluxed for 3 min, with 3.2 cm. of thiethylamine. The dyestufi, which crystallizes on cooling, is sucked off and recrystallized from dimethylformamide. Melting point: 290 C. Absorption maximum: 506 me. Log. .6: 5.01.

Example 15 The methine dye (15-00) of the formula:

34 Example 16 The methine dye (16-00) of the formula:

is prepared as follows:

A mixture of 2.75 g. of 5-methyl-6,1l-dihydrobenzimidazolo[1,2-b]isoquinolinium iodide (76A0l-Ql'), 1.81 g. of 1,3 diethyl-5,6-dichloro-2-[/3-(p-t'olusulfanilido)vinyl] benzirnidazolium chloride, cml of methanol and 1.4 cm. of triethylamine is refluxed for 5 min. After cooling the formed dyestulf is sucked off, washed with ethanol and ether and twice recrystallized from ethylene glycol monomethyl ether. Melting point: 270 C. Absorption maximum: 502 me. Log 62 4.960.

Example 17 The methine dye (17-00) of the formula:

is prepared as follows:

1.73 g. of 5,7-diethyl-1,2,3,4,8,9,10,1l-octahydrodipyridino[1,2 a:l,2' a]benzo[1,2 d:5,4-d"]diimidazolium diiodide (7A01-Q2), 149 g. of 2 (,8 anilinovinyl) 3- ethylthiazolinium bromide dissolved in 20 cm; of .acetic anhydride and 1.7 cm. of triethylamine are refluxed for 45 minutes. After cooling, the dyestuff is precipitated with ether and purified by recrystallization from ethanol. Melting point: 320 C. Absorption maximum: 548 m Log. e: 5.30.

Example 18 The methine dye (18-00) of the formula:

is prepared as follows:

A mixture of 3.5 g. of 4- ethyl-.6-chlor,o-.2,3:dihydro-1H- pyrrolo[1,2+a]benzimidazolium iodide (1A01.,Q2 3.1 g. of 3-ethyl-S-aoetanilidomethylene 2-thio-2,4:thiazolidinedione, 25 cm. of pyridine and 2.18 cr n of triethylamine is refluxed for '1 h. After cooling, the .dyestulf is precipitated with Water, sucked ,off and recrystallized from ethylene glycol monomethyl ether. Melting point: 294 C. Absorption maximum: 524 me. Log. s! 4.95.

35 Example 19 The methine dye (19-00) of the formula:

is prepared as follows:

3.14 g. of 4-ethy1-2,3-di-hydro-lH-pymrolo[ l,2a] benzimidazolium iodide (0A01-Q2), 2.9 g. of 3-ethyl-5-acetanilidomethylene-2-thio-2,4-oxazolidine dione, 25 cm. of methyl carbitol and 2.8 cm. of triethylamine are refluxed for 20 min. After cooling, the dyestuff is precipitated with water and purified by recrystallization from a mixture of methyl carbitol and ethanol (1:1). Melting point: 160 C. Absorption maximum: 498 m is prepared as follows:

1.8 g. of 2-thio-3-ethyl-5-[4(5-e;thy1-7-chlor0-1,2,3,4- tetrahydropyridino[l,2 a]benzimidazol yl) methylideneJ-ZA-thiazolidine dione 18-12) are dissolved in 150 cm. of water-free benzene, 0.58 cm. of dimethyl sulfate is added and the reaction mixture is refluxed for 4 h. on an oil-bath at 120 C. The quaternized merocyanine dye crystallizes on cooling. The dye is sucked off and washed with ether. Melting point: 180 C. Absorption maximum: 526 m Example 21 The methine dye (21-00) of the following formula:

' is prepared as follows:

1.7 g. of the quaternized merocyanine dye obtained according to Example 20, 0.6 g. of 3-ethyl-2-thio-2,4-thiazolidine dione, 20 cm. of pyridine and 0.5 cm. of triethylamine are refluxed for 2 to 3 minutes. Thereupon cm. of pyridine are added and the reaction mixture is allowed to cool. The formed dyestufi is sucked off and washed with ethanol and ether. The crude dyestuff is recrystallized three times from pyridine, once from a mixture of dimethyl formamide and n-propanol and once from ethylene glycol monomethyl ether. Melting point: 260 C. Absorption maximum: 592 me; Log. e: 5.124.. 1

36 Example 22 The methine dye (22-00) of the following formula:

H2 H2 s C- is prepared as follows:

0.53 g. of the quaternized merocyanine dye obtained according to example 20 and 0.31 g. of 2,5-dimethyl-3- ethylbenzothiazolium methyl sulfate are suspended in 15 cm. of pyridine and 0.14 cm. of triethyl amine. This reaction mixture is refluxed for 2 to 3 minutes. The dyestuif crystallizes during the refluxing. After cooling, the dyestuif is sucked off and washed with ethanol and ether. The dyestuif is first recrystallized from ethanol and then from ethylene glycol monomethyl ether. Melting point: 260 C. Absorption maximum: 605 me. Log. c2 4.943.

Example 23 The methine dye (23-00) of the following formula:

sCz- N l is prepared as follows:

3.32 g. of 3-ethyl-5-(w-acetanilidopropenylidene)-2- thio-2,4-thiazolidine dione and 3.625 g. of 5-ethy1-7-chloro- 1,2,3,4-tetrahydropyridino 1,2-a] benzimidazolium iodide (1Al2-Q2) are dissolved in 70 cm. of dimethyl sulfoxide without boiling the mixture. Then 1.4 cm. of triethylamine are added and the mixture is heated for 2 h. on .a water-bath of C. Thereupon the reaction mixture is cooled in an acetone-ice bath until the dimethyl sulfoxide solidifies. Then 210 cm. of water are added and the mixture is kept overnight in a refrigerator. The solid product is sucked off and twice washed with boiling petroleum naphtha (boiling range: 90-120 C.) The washed product is boiled in cm. of water and recrystallized from ethanol. Melting point: decomposition. Absorption maximum: 615 III/1..

Example 24 The methine dye (24 00) of the following formula:

8 ea s=o \C=CH CzHs is prepared as follows:' 2.89 g. of 5,7-diethy1-1,2,3,4,8,9,10,-1l-octahydro-dipyridino [1,2-a:1,2-a7]benzo['1,2-d:5,4-d]diimidazolium diiodide (7A01-Q2) are dissolved in 80 cm. of dimethyl sulfoxide without boiling. Then 3.06 g. of 3-ethyl-S-acetani-lidomethylene-2-thio-2,4-thiazolidine dione and 2.8 cm. of triethylamine are added. This mixture is heated for 3 h. on a water-bath of 95 C. whereupon 1.4 cm. of triethylamine are added and heating is continued for two hours. 100 cm. of methanol are added to the solution whilst warm. After the formed dyestufi is sucked off, and washed several times with methanol, once with ethanol and once with petroleum naphtha, the dyestufr is recrystallized twice 'from a mixture of phenol and methanol. Melting point: 260 C. Absorption maximum: 620mg. Log 62 5.460.

Example 25 The methine dye (25-00) of the formula:

is prepared .as follows:

. 25 To 1.5 g. of dimethylaminobenzaldehyde and 3.14 g.

38 for 15 min. The dye which crystallizes out on cooling is purified by recrystallizing twice from ethanol. Melting point: 270 C. Absorption maximum: 429rnp. Log 62 4.13.

Example 26 The methine dye (26-00) of the following formula:

Se N Cl I r- 2 s 2)4SOzNHCOCH is prepared as follows:

4.85 g. of 4-(w-aeetylsulfonamidehutyl)-6,7-dich1oro- 2,3-dihydro-lH-pyrrolo[ 1,Q-a]henzimidazoliurn bromide (1A03-Q6) are dissolved in 125 cm. of 1-methoxy-2-(2- hydroxyethoxy)-ethane (methylcarbitol). The solution is heated to 100 C. and at this temperature 4.49 g. of 2-(,8-acetanilidovinyl) 3 ethylselenazolium iodide and then 2.8 cm. of triethylamine are added. The reaction mixture is kept for 10 minutes at 100 C. whereupon it is cooled. The dyestuflf is precipitated by adding 200 cm. of ether. Thereupon the ether is decanted and the crude dyestuff is washed with methanol. Finally the dyestuif is recrystallized twice from dimethyl formamide. Melting point: 260 C. Absorption maximum: 47-8 mp TABLE M Number of Number of reference Melting Absorption reference of Structural formula of the point, man, my. Log 2 the methine quaternary C.

dye salt NC H /NC\ /OC\ H O C=OHC\ /CH 1* CO CN H:

H C lf 02-02 13 Hz 1A06-Q1 260 532 l' I (fHn H C I| I 1 CC=CH H5C1OOC C0OC;|H I- g CH 02-03 H: H; 5A01-Q3 220-24 537 4. 97

C N CH, H O III 0- =CH- --0 NC N B1- CHPCH -O-O OOH, CH CH OOO'CH 04-01 H1 lAO'l-QZ 250 462 5.03

s H Cl) %!7CH=CHC C\ mo IThf C2H5 CZHS 

1. PHOTOGRAPHIC SILVER HALIDE EMULSION CONTAINING A METHINE DYE SALT REPRESENTED BY A FORMULA SELECTED FROM THE GROUP CONSISTING OF: 